Avoid converting key to string for deleting of elements

Avoid converting key to string for deleting of elements
Additionally rips out (now) unnecessary duplicate code in DefineArrayProperty.

BUG=

Committed: https://crrev.com/d5335cba314dbef8a6d090703efcb33fe4009676
Cr-Commit-Position: refs/heads/master@{#29450}

[Toon Verwaest, 2015-07-02 12:59:03]

verwaest@chromium.org changed reviewers:
+ jkummerow@chromium.org

[Toon Verwaest, 2015-07-02 12:59:04]

ptal

[Jakob Kummerow, 2015-07-02 13:24:53]

LGTM

https://codereview.chromium.org/1224523002/diff/1/src/v8natives.js
File src/v8natives.js (right):

https://codereview.chromium.org/1224523002/diff/1/src/v8natives.js#newcode806
src/v8natives.js:806: // property, hence we use generated code throughout this
function instead of
nit: outdated comment

[Toon Verwaest, 2015-07-02 13:31:26]

The CQ bit was checked by verwaest@chromium.org

[Toon Verwaest, 2015-07-02 13:31:27]

The patchset sent to the CQ was uploaded after l-g-t-m from
jkummerow@chromium.org
Link to the patchset: https://codereview.chromium.org/1224523002/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-07-02 13:31:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1224523002/20001

[commit-bot: I haz the power, 2015-07-02 14:15:58]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-02 14:15:59]

Try jobs failed on following builders:
  v8_linux_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_rel/builds/7244)

[Jakob Kummerow, 2015-07-02 15:01:49]

lgtm

[Toon Verwaest, 2015-07-02 15:02:07]

The CQ bit was checked by verwaest@chromium.org

[commit-bot: I haz the power, 2015-07-02 15:02:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1224523002/60001

[commit-bot: I haz the power, 2015-07-02 15:27:27]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-07-02 15:27:38]

Patchset 4 (id:??) landed as
https://crrev.com/d5335cba314dbef8a6d090703efcb33fe4009676
Cr-Commit-Position: refs/heads/master@{#29450}